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Amelioration of scopolamine induced cognitive dysfunction and oxidative stress by Inonotus obliquus - a medicinal mushroom
Abstract
The present study was aimed to investigate the cognitive enhancing and anti-oxidant activities of Inonotus obliquus (Chaga) against scopolamine-induced experimental amnesia. Methanolic extract of Chaga (MEC) at 50 and 100 mg kg (-1)doses were administered orally for 7 days to amnesic mice. Learning and memory was assessed by passive avoidance task (PAT) and Morris water maze (MWM) test. Tacrine (THA, 10 mg kg (-1), orally (p.o)) used as a reference drug. To elucidate the mechanism of the cognitive enhancing activity of MEC, the activities of acetylcholinesterase (AChE), anti-oxidant enzymes, the levels of acetylcholine (ACh) and nitrite of mice brain homogenates were evaluated. MEC treatment for 7 days significantly improved the learning and memory as measured by PAT and MWM paradigms. Further, MEC significantly reduced the oxidative-nitritive stress, as evidenced by a decrease in malondialdehyde and nitrite levels and restored the glutathione and superoxide dismutase levels in a dose dependent manner. In addition, MEC treatment significantly decreased the AChE activity in both the salt and detergent-soluble fraction of brain homogenates. Further, treatment with MEC restored the levels of ACh as did THA. Thus, the significant cognitive enhancement observed in mice after MEC administration is closely related to higher brain anti-oxidant properties and inhibition of AChE activity. These findings stress the critical impact of Chaga, a medicinal mushroom, on the higher brain functions like learning and memory.
... Among medicinal mushrooms, Phellinus linteus (PL), Ganoderma lucidum (GL), and Inonotus obliquus (IO) are the most important species that have been widely consumed as oriental therapeutics [31]. All three species have been demonstrated to reduce the infarct volume and neurological deficits in fCI animal models when orally administered as a form of either fruit body or mycelium [32][33][34]. Based on these notions, we would expect a certain degree of therapeutic synergism when the PL, GL, and IO are administered in combination. ...
... A large body of evidence indicates that edible mushrooms possess various healthpromoting properties including anticancer, antibacterial, antifungal, antiviral, immunomodulating, antiallergic, antidepressive, antihyperlipidemic, antidiabetic, hepatoprotective, nephroprotective, osteoprotective, and hypotensive activities in addition to, remarkably, anti-oxidative activities [17][18][19][20][21][22][23][24]57]. Among mushrooms, PL, GL, and IO are reported to have outstanding neuroprotective effects [32][33][34]. PL extract has dose-dependent protective effects on oxidative stress-induced apoptosis by diminishing Cleaved caspase-3 and ROS levels and increasing the expression of HO-1, CAT, and SOD in SK-N-MC cells, a human neuroblastoma cell line [58]. In the case of GL, it has been reported to protect cultured cerebellar granule cells against H 2 O 2 -a ROS donor-induced apoptosis by decreasing the expression of caspase-3, Bax, and Bim and increasing that of Bcl-2 [59]. ...
Although the individual consumption of medicinal mushrooms, including Phellinus linteus (PL), Ganoderma lucidum (GL), and Inonotus obliquus (IO), is known to be neuroprotective, the associated mechanisms underlying their therapeutic synergism on focal cerebral ischemia (fCI) have yet to be elucidated. This study aimed to demonstrate the neuroprotective effects of mixed mushroom mycelia (MMM) against experimental fCI. The water-fractions, ethanolic-fractions, and ethyl acetate-fractions of the MMM (PL, GL, and IO) grown in a barley medium using solid-state fermentation techniques were prepared and their protective effects against glutamate-induced excitotoxicity were compared in PC-12 cells. After the identification of the water extracts of MMM (wMMM) as the most suitable form, which possessed the lowest toxicity and highest efficacy, further analyses for evaluating the anti-apoptotic effects of wMMM, including Hoechst 33258-based nuclear staining, fluorescence-activated cell sorting, and reactive oxygen species (ROS) detection assays, were performed. Rats were subjected to a 90 min middle cerebral artery occlusion and reperfusion, after which a wMMM treatment resulted in significant dose-dependent improvements across a number of parameters. Furthermore, measurements of intracellular ROS and levels of antioxidant enzymes revealed a wMMM-mediated ROS attenuation and antioxidant enzyme upregulation. We suggest that wMMM is neuroprotective against fCI through its anti-apoptotic and anti-oxidative effects.
... Besides cholinergic hypothesis, the role of oxidative stress in the initiation of cognitive debility has further unleashed a promising avenue for drug development in this area (Berr 2002). Scopolamine induced animal model of cognitive deterioration has been extensively employed for the purpose of research on molecules designed for the therapy of dementia (Budzynska et al. 2015); (Giridharan et al. 2011). Sopolamine, a muscarinic antagonist, affects the cognitive skills of an individual by interfering with their learning and memory patterns. ...
... Due to wide implication of oxidative stress in neurological diseases, antioxidant therapy has been employed as a treatment approach in a variety of neurodegenerative disorders (Jomova et al. 2010); (Uttara et al. 2009). Scopolamine, in addition to the disruption of cholinergic neurotransmission, also has an association with oxidative damage that results in cognitive impairment (Budzynska et al. 2015); (Giridharan et al. 2011). With this background, the present study was designed to investigate the effects of newly synthesised analogues of the parent 1,3,4-thiadiazoles on the scopolamine induced oxidative stress. ...
Acetylcholinesterase has been a promising target for the development of putative therapeutics against cognitive decline. The deleterious effect of oxidative stress on the learning and memory paradigms of an individual has also been well documented. In view of this and our previous findings on the ameliorative effects of amide derivatives of 1,3,4-thiaidiazoles on cognitive deterioration, the present study demonstrated the design, synthesis and pharmacological evaluation of carboxamides and carbothioamide derivatives of 1,3,4-thiadiazole. Novel carboxamide and carbothioamide derivatives were synthesised and characterised by various spectral and elemental techniques. Their effects on memory were studied by employing scopolamine induced amnesia in two behavioural animal models: Morris water maze and passive avoidance (dose of 0.5 mg/kg) with reference to the standard, Rivastigmine. In vitro AChE inhibition was studied at five different concentrations using the homogenised fraction of the decapitated mice brain as the source of the enzyme. Biochemical estimation of AChE, oxidative and nitrosative stress parameters have also been facilitated. Computational docking studies have been performed on human recombinant AChE (PDB ID: 4EY7) to assess the binding conformation of the molecules. The results indicated that the carbothioamide analogues 13a, 9b and 10b were found to be the most promising in the alleviation of cognitive decline induced by scopolamine. Among the carboxamide analogues, 8b has shown promising effect in the alleviation of cognition decline. Our results suggested the possible role of these derivatives in the mediation of cholinergic pathway and attenuation of oxidative stress resulting in the effective management of cognitive dysfunction.
... 37 In the present study, we used two well-characterized memory tasks: Y-maze test and MWM test in rats to investigate the protective effect of Spondia mombin and Cola acuminata against scopolamine-induced memory impairment. Scopolamine is well known for its amnesic effect in animals and human 38,39 and its pretrial administration caused cognitive impairment in both the Y-maze and MWM tests. 8 Scopolamine-induced cognitive dysfunction has been reported to be associated with impairment in central cholinergic system which plays an important role in learning and memory. ...
... Previous studies showed that scopolamine induced amnesia is associated with increased oxidative stress in brain. 7,39 In the present study, we found increased oxidative and nitrosative stresses evidenced in elevated MDA and nitrite levels in the prefrontal cortex, hippocampus and striatum of scopolamine-treated rats brain. Scopolamine was also found to disturb metabolism, especially for low molecular weight antioxidants such as glutathione, and therefore intensify the level of lipids peroxidation within the brain, 42 which is particularly vulnerable to reactive oxygen species (ROS) action due to high abundance of highly oxidizable polyunsaturated fatty acids. ...
The leaves of Spondias mombin L. (Anacardiaceae) when chewed with Cola acuminata (P. Beauv.) Schott & Endl. (Sterculiaceae) seeds have memory enhancing and anti-ageing properties. This study sought to investigate the protective effect of hydroethanolic leaf extract of Spondias mombin (SM) and Cola acuminata seed extract (CA) against scopolamine-induced cognitive dysfunction. SM or CA (50, 100 or 200 mg/kg, p.o.) or SM + CA (50 mg/kg, p.o.) was administered to rats for 3 consecutive days. One hour post-treatment on day 3, scopolamine (3 mg/kg i.p) was administered and 5 min later, the Y-maze test or Morris water maze test (MWM; days 3–7) was conducted. The rat’s brains were isolated for the estimation of oxidative-nitritive stress status following the MWM task. The antioxidant capacity of SM and CA was also evaluated in vitro using the 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric ion reducing power (FRAP) assays. Pretreatment of rats with SM, CA or SM + CA significantly ameliorated the learning and memory impairment induced with scopolamine as evidenced in Y-maze and MWM paradigms. Moreover, SM, CA or SM + CA significantly attenuated the oxidative-nitritive stress induced by scopolamine, evidenced in the decrease in malondialdehyde and nitrite levels and restoration of glutathione, catalase and superoxide dismutase levels. Furthermore, SM and CA showed promising free radical scavenging effect against DPPH and moderate antioxidant activity in NO and FRAP tests. This study showed that Spondias mombin and Cola acuminata have significant protective effect against scopolamine-induced memory deficit that could be attributed to their antioxidant properties.
... Chaga (Inonotus obliquus, also known as cinder conk) is a parasitic fungus found on birch trees; it has a long history of a wide variety of medicinal uses in Asia and Eastern Europe, as well as in Alaska. Chaga extracts exhibit high antioxidant activity (Cui et al., 2005) and protect rat neuronal cells against oxidative stress (Giridharan et al., 2011). Korean traditional knowledge heralds chaga for its anti-cancer effects (Kim and Song, 2014) and ergosterol peroxide extracted from chaga was recently shown to inhibit cell growth by promoting apoptosis in a colorectal cancer cell model (Kang et al., 2015). ...
... Chaga extract contained the lowest polyphenol levels of the studied extracts, yet, endogenous ROS levels of C. elegans following consumption of chaga extract support previous studies demonstrating that chaga extracts exert potent antioxidant effects (Figure 4) (Cui et al., 2005;Giridharan et al., 2011). While chaga contains polyphenolic compounds (Lee et al., 2007), the fungus also contains unique non-polyphenolic bioactive secondary compounds, such as steroid derivatives. ...
Many nutritional interventions that increase lifespan are also proposed to postpone age-related declines in motor and cognitive function. Potential sources of anti-aging compounds are the plants and fungi that have adapted to extreme environments. We studied the effects of four commonly consumed and culturally relevant Interior Alaska berry and fungus species (bog blueberry, lowbush cranberry, crowberry, and chaga) on the decline in overall health and neuron function and changes in touch receptor neuron morphology associated with aging. We observed increased wildtype Caenorhabditis elegans lifespan and improved markers of healthspan upon treatment with Alaskan blueberry, lowbush cranberry, and chaga extracts. Interestingly, although all three treatments increased lifespan, they differentially affected the development of aberrant morphologies in touch receptor neurons. Blueberry treatments decreased anterior mechanosensory neuron (ALM) aberrations (i.e. extended outgrowths and abnormal cell bodies) while lowbush cranberry treatment increased posterior mechanosensory neuron (PLM) aberrations, namely process branching. Chaga treatment both decreased ALM aberrations (i.e. extended outgrowths) and increased PLM aberrations (i.e. process branching and loops). These results support the large body of knowledge positing that there are multiple cellular strategies and mechanisms for promoting health with age. Importantly, these results also demonstrate that although an accumulation of abnormal neuron morphologies is associated with aging and decreased health, not all of these morphologies are detrimental to neuronal and organismal health.
... . Learning and memory function depends on the activation of neurotransmitters, such as ACh, dopamine, and serotonin, which transmits external signals to the intercellular messengers [5]. Moreover, it has been shown that ACh plays an important role in the hippocampal mode shifting between encoding and retrieval [6]. ...
Alzheimer’s disease (AD) is a neurodegenerative disorder, characterized by memory loss and cognitive decline. Among the suggested pathogenic mechanisms of AD, the cholinergic hypothesis proposes that AD symptoms are a result of reduced synthesis of acetylcholine (ACh). A non-selective antagonist of the muscarinic ACh receptor, scopolamine (SCOP) induced cognitive impairment in rodents. Umbelliferone (UMB) is a Apiaceae-family-derived 7-hydeoxycoumarin known for its antioxidant, anti-tumor, anticancer, anti-inflammatory, antibacterial, antimicrobial, and antidiabetic properties. However, the effects of UMB on the electrophysiological and ultrastructure morphological aspects of learning and memory are still not well-established. Thus, we investigated the effect of UMB treatment on cognitive behaviors and used organotypic hippocampal slice cultures for long-term potentiation (LTP) and the hippocampal synaptic ultrastructure. A hippocampal tissue analysis revealed that UMB attenuated a SCOP-induced blockade of field excitatory post-synaptic potential (fEPSP) activity and ameliorated the impairment of LTP by the NMDA and AMPA receptor antagonists. UMB also enhanced the hippocampal synaptic vesicle density on the synaptic ultrastructure. Furthermore, behavioral tests on male SD rats (7–8 weeks old) using the Y-maze test, passive avoidance test (PA), and Morris water maze test (MWM) showed that UMB recovered learning and memory deficits by SCOP. These cognitive improvements were in association with the enhanced expression of BDNF, TrkB, and the pCREB/CREB ratio and the suppression of acetylcholinesterase activity. The current findings indicate that UMB may be an effective neuroprotective reagent applicable for improving learning and memory against AD.
... Other studies on rat liver tissue supported that IOP suppressed thiobarbituric acid reactive substance formation in Fe 2+ /ascorbate-induced lipid peroxidation . Treatment of scopolamine-induced memory-deficient mice with a methanolic extract of I. obliquus decreased the nitrite, GSSG/GSH ratio, and MDA levels, whereas levels of antioxidant enzymes such as superoxide dismutase (SOD) and reduced glutathione (GSH) were increased (Giridharan, Thandavarayan, & Konishi, 2011). A study in PC12 cells reported ...
The use of mushrooms as functional foods and in the treatment of diseases has a long history. Inonotus obliquus is a mushroom belonging to the Hymenochaetaceae family and has possible anticancer, antiviral, and hypoglycemic properties. Chemical analysis of this mushroom has allowed the identification of various constituents such as melanins, phenolic compounds, and lanostane-type triterpenoids. A plethora of findings have highlighted the potential molecular mechanisms of actions of this mushroom such as its ability to scavenge reactive oxygen species, inhibit the growth of tumors, decrease inflammation and insulin resistance in type 2 diabetes, and stimulate the immune system. This review summarizes the relevant findings with reference to the therapeutic potential of this mushroom in countering the progression of cancers, diabetes mellitus, and antiviral activities, while highlighting its possible molecular mechanisms of action. The possible role of this mushroom as a therapeutic agent in addressing the pathogenesis of diabetes and cancer has also been suggested.
... Reactive oxidative species (ROS) are able to deficit cellular constituents and play an important role as a secondary messenger mediating inflammation [16]. Prior researches reported that oxidative stress is associated with memory dysfunction in the SCO-induced animal model of amnesia [17][18][19][20][21]. ...
Increasing evidence suggests that neurodegenerative disorders such as Alzheimer’s disease (AD) are mediated via disruption of cholinergic neurons and enhanced oxidative stress. Therefore, attention has been focused on searching for antioxidant phytochemicals for the prevention and/or treatment of AD through their ability to fortify cholinergic function and antioxidant defense capacity. In this study, we have investigated the neuroprotective effect of α -pinene (APN) against learning and memory impairment induced by scopolamine (SCO, 1 mg/kg, i.p.), a muscarinic receptor antagonist in C57BL/6 mice. Administration of APN (10 mg/kg, i.p.) significantly improved SCO-induced cognitive dysfunction as assessed by Y-maze and passive avoidance tests. In Morris water-maze test, APN effectively shortened the mean escape latency to find the hidden platform during training days. To further elucidate the molecular mechanisms underlying the neuroprotective effect of APN, the expression of proteins involved in the acetylcholine metabolism and antioxidant system was examined. Particularly, APN treatment increased mRNA expression of choline acetyltransferase in the cortex and protein levels of antioxidant enzymes such as heme oxygenase-1 and manganese superoxide dismutase in the hippocampus via activation of NF-E2-related factor 2. These findings suggest the possible neuroprotective potentials of APN for the management of dementia with learning and memory loss.
... It has been shown that Dictyoquinazols extracted from Dictyophora indusiata protect primary cultured mouse cortical neurons from glutamate-and NMDA-induced excitotoxicities (Lee et al., 2002). Furthermore, the methanolic extract of Chaga enhances the cognitive and anti-oxidant activities of scopolamine-induced experimental amnesia (Giridharan et al., 2011). In addition, the oligosaccharide fraction isolated from the mycelium of the Lingzhi and/or Reishi medicinal mushroom Ganoderma lucidum exhibits anticonvulsant and neuroprotective effects (Tello et al., 2013). ...
Alzheimer’s disease (AD) is the most common neurodegenerative disorder, affecting approximately more than 5% of the population worldwide over the age 65, annually. The incidence of AD is expected to be higher in the next 10 years. AD patients experience poor prognosis and as a consequence new drugs and therapeutic strategies are required in order to improve the clinical responses and outcomes of AD. The purpose of the present study was to screen a certain number of potential compounds from herbal sources and investigate their corresponding mode of action. In the present study, the learning and memory effects of ethanol:water (8:2) extracts from Hericium erinaceus were evaluated on a dementia rat model. The model was established by intraperitoneal injection of 100 mg/kg/d D-galactose in rats. The results indicated that the extracts can significantly ameliorate the learning and memory abilities. Specific active ingredients were screened in vivo assays and the results were combined with molecular docking studies. Potential receptor–ligand interactions on the BACE1-inhibitor namely, 3-Hydroxyhericenone F (3HF) were investigated. The isolation of a limited amount of 3HF from the fruit body of H. erinaceus by chemical separation was conducted, and the mode of action of this compound was verified in NaN3-induced PC12 cells. The cell-based assays demonstrated that 3HF can significantly down-regulate the expression of BACE1 (p < 0.01), while additional AD intracellular markers namely, p-Tau and Aβ1-42 were further down-regulated (p < 0.05). The data further indicate that 3HF can ameliorate certain mitochondrial dysfunction conditions by the reversal of the decreasing level of mitochondrial respiratory chain complexes, the calcium ion levels ([Ca2+]), the inhibiton in the production of ROS, the increase in the mitochondrial membrane potential and ATP levels, and the regulation of the expression levels of the genes encoding for the p21, COX I, COX II, PARP1, and NF-κB proteins. The observations suggest the use of H. erinaceus in traditional medicine for the treatment of various neurological diseases and render 3HF as a promising naturally occurring chemical constituent for the treatment of AD via the inhibition of the β-secretase enzyme.
... 2 In recent years, researchers have begun to pay attention to the health impacts of mushrooms. Several in vivo 3,4 and in vitro 5 experiments have suggested that mushrooms have beneficial effects on cognitive function. Some animal experiments have revealed that mushrooms can protect cells from oxidative damage [6][7][8] and inflammation, 9,10 both of which have been implicated in the pathogenesis of dementia. ...
Background:
Both in vivo and in vitro studies have indicated that edible mushrooms may have preventive effects against cognitive impairment. However, few cohort studies have yet examined the relationship between mushroom consumption and incident dementia.
Objective:
We examined the relationship between mushroom consumption and incident dementia in a population of elderly Japanese subjects.
Design:
Prospective cohort study.
Setting:
Ohsaki Cohort 2006 Study.
Participants:
13,230 individuals aged ≥65 years living in Ohsaki City, northeastern Japan.
Measurements:
Daily mushroom consumption, other lifestyle factors, and dementia incidence.
Results:
The 5.7 years incidence of dementia was 8.7%. In comparison with participants who consumed mushrooms <1 time/wk, the multi-adjusted HRs (95% CI) for incident dementia among those did so 1-2 times/week and ≥3 times/week were 0.95 (0.81, 1.10) and 0.81 (0.69, 0.95), respectively (P-trend <.01). The inverse association persisted after excluding participants whose dementia event occurred in the first 2 years of follow-up and whose baseline cognitive function was lower. The inverse association did not differ statistically in terms of vegetable consumption (P-interaction = .10).
Conclusions:
This cohort study suggests that frequent mushroom consumption is significantly associated with a lower risk of incident dementia, even after adjustment for possible confounding factors.
... Scopolamine (PubChem CID: 5184) is known as an antagonist of muscarinic acetylcholine receptor [4], and causing memory impairment in rodents [5,6] and humans [7]. In addition, scopolamine induces oxidative stress in brain [8], and reduces formation of brain-derived neurotrophic factor (BDNF) in neuronal cells [9]. Therefore, administration of scopolamine for in vivo experiment is generally used as a model of memory impairment for Alzheimer's disease. ...
N-Acetyl serotonin (NAS) as a melatonin precursor has neuroprotective actions. Nonetheless, it is not clarified how NAS protects neuronal cells against oxidative stress. Recently, we have reported that N-palmitoyl serotonins possessed properties of antioxidants and neuroprotection. Based on those, we hypothesized that NAS, a N-acyl serotonin, may have similar actions in oxidative stress-induced neuronal cells, and examined the effects of NAS based on in vitro and in vivo tests. NAS dose-dependently inhibited oxidative stress-induced cell death in HT-22 cells. Moreover, NAS suppressed glutamate-induced apoptosis by suppressing expression of AIF, Bax, calpain, cytochrome c and cleaved caspase-3, whereas it enhanced expression of Bcl-2. Additionally, NAS improved phosphorylation of tropomyosin-related kinase receptor (TrkB) and cAMP response element-binding protein (CREB) as well as expression of brain-derived neurotrophic factor (BDNF), whereas the inclusion of each inhibitor of JNK, p38 or Akt neutralized the neuroprotective effect of NAS, but not that of ERK. Meanwhile, NAS dose-dependently reduced the level of reactive oxygen species, and enhanced the level of glutathione in glutamate-treated HT-22 cells. Moreover, NAS significantly increased expression of heme oxygenase-1, NAD(P)H quinine oxidoreductase-1 and glutamate-cysteine ligase catalytic subunit as well as nuclear translocation of NF-E2-related factor-2. Separately, NAS at 30 mg/kg suppressed scopolamine-induced memory impairment and cell death in CA1 and CA3 regions in mice. In conclusion, NAS shows actions of antioxidant and anti-apoptosis by activating TrkB/CREB/BDNF pathway and expression of antioxidant enzymes in oxidative stress-induced neurotoxicity. Therefore, such effects of NAS may provide the information for the application of NAS against neurodegenerative diseases.
... Besides the cholinergic hypothesis, neurodegenerative disease, including Alzheimer's disease, are also associated with oxidative damage in the brain resulting from an imbalance between reactive oxygen species generation and antioxidant enzyme activity (Wong et al., 2012;Sayyad et al., 2016;Ser et al., 2016). Previous reports revealed that several mushrooms have been demonstrated to exhibit cognitive enhancing activity including Hericium erinaceus (Yamabushitake) (Mori et al., 2009), Inonotus obliquus (Chaga) (Giridharan et al., 2011) and Cordyceps militaris (Tsai et al., 2015). Several recent studies have also sought to investigate the beneficial effects of F. velutipes in cognitive function improvement (Yang et al., 2011. ...
Flammulina velutipes (enoki, velvet shank, golden needle mushroom or winter mushroom), one of the main edible mushrooms on the market, has long been recognised for its nutritional value and delicious taste. In recent decades, research has expanded beyond detailing its nutritional composition and delved into the biological activities and potential health benefits of its constituents. Many bioactive constituents from a range of families have been isolated from different parts of the mushroom, including carbohydrates, protein, lipids, glycoproteins, phenols and sesquiterpenes. These compounds have been demonstrated to exhibit various biological activities, such as antitumour and anticancer activities, anti-atherosclerotic and thrombosis inhibition activity, antihypertensive and cholesterol lowering effects, anti-aging and antioxidant properties, ability to aid with restoring memory and overcoming learning deficits, anti-inflammatory, immunomodulatory, anti-bacterial, ribosome inactivation and melanosis inhibition. This review aims to consolidate the information concerning the phytochemistry and biological activities of various compounds isolated from Flammulina velutipes to demonstrate that this mushroom is not only a great source of nutrients but also possesses tremendous potential in pharmaceutical drug development.
... The mechanisms underlying the induction of oxidative stress following scopolamine treatment are not yet elucidated; however, many experiments have demonstrated the presence of oxidative stress in scopolamine-induced animal models (Giridharan et al. 2011;Pachauri et al. 2012). Moreover, free radicals are thought to cause behavioural deficits in experimental animals (Fukui et al. 2002). ...
The development of agents that affect two or more relevant targets has drawn considerable attention in treatment of AD. Diallyl disulfide (DADS), an active principle of garlic, has been reported to prevent APP processing by amyloidogenic pathway. Recently, we have reported a new series of DADS derivatives and our findings revealed that compound 7k and 7l could provide good templates for developing new multifunctional agents for AD treatment. Thus, the present study was constructed to investigate the neuroprotective effect of DADS analogues (7k and 7l) against Aβ-induced neurotoxicity in SH-SY5Y human neuroblastoma cells and in ameliorating the cognition deficit induced by scopolamine in rat model. The results indicated that compound 7k and 7l significantly inhibited Aβ1–42-induced neuronal cell death by inhibiting ROS generation. Moreover, they prevented apoptosis, in response to ROS, by restoring normal Bax/Bcl-2 ratio. Furthermore, it was observed that scopolamine-induced memory impairment was coupled by alterations in neurotransmitters, acetylcholinesterase activity and oxidative stress markers. Histological analysis revealed severe damaging effects of scopolamine on the structure of cerebral cortex and hippocampus. Administration of compounds 7k and 7l at 5 mg/kg significantly reversed scopolamine-induced behavioural, biochemical, neurochemical and histological changes in a manner comparable to standard donepezil. Together the present findings and previous studies indicate that compounds 7k and 7l have neuroprotective and cognition-enhancing effects, which makes them a promising multi-target candidate for addressing the complex nature of AD.
... For millennia, mushrooms have been valued as edible and medical provisions for humankind. These species comprise a vast and yet largely untapped source of powerful pharmaceutical products which may be applied in the treatment of gastrointestinal disorders, various forms of cancers, bronchial asthma, etc. (4,5). Pyropolyporus fomentarius (L. ...
Pyropolyporus fomentarius (L. ex Fr.) Teng is a unique woody mushroom due to its medicinal value with numerous pharmacological activities. This study presented the potential antitumor and immunomodulatory properties of ethanol extract of P. fomentarius. The results showed that P. fomentarius extract inhibited the viability of murine leukemia L1210 cells in a dose-dependent manner with IC50 value of 69.35 μg/ml. Flow cytometry analysis demonstrated that the extract induced apoptosis in L1210 cells. Additionally, the decline of mitochondrial membrane potential was observed as well as the changes of caspase-3, caspase-9, Bcl-2, and Bax, suggesting that proapoptosis effect of the extract involved mitochondria-related pathway. Simultaneously, the P. fomentarius extract significantly enhanced the proliferation and activation of splenic lymphocytes in a dose-dependent manner. This P. fomentarius extract has potential applications as a natural antitumor agent with immunomodulatory activity.
... Pan et al. (2013) reported that chaga water extract exhibits marked decline in HSV-1 infection, the mechanism being the inhibition of viral-induced membrane fusion leading to the prevention of viral entry. Giridharan et al. (2011) investigated the cognitive stimulation and antioxidant activities of chaga against scopolamine-induced experimental amnesia (memory loss). Chaga methanolic extract at 50-100 mg/kg doses were administered orally for 7 days to test mice. ...
Chaga mushroom (Inonotus obliquus) is a white-rot fungus growing on birch trees. It looks like burnt coal, has edibility and is regarded a traditional medicinal mushroom in China, Russia, Poland, other Baltic countries. It is hailed as a folk remedy against diabetes, digestive disorders, intestinal worms, liver ailments, cardiovascular diseases, tuberculosis and cancer etc. Recently, it has grabbed attention from mainstream medicine as a therapeutic mushroom. The discovery of a diverse range of secondary metabolites including, phenolic compounds, polysaccharides, melanins, lanosterol, inotodiol, ergosterol and trametenolic acid have promoted it as a potential drug candidate. Biological roles as antioxidant, antiinflammation, anticancer, immunomodulation, antiallergy, antilipemic, hypoglycaemic, antiviral, neurostimulation have been validated. This chapter delves into the biological roles and mechanisms governing the effects.
... In another study using the peroxide-treated human fibroblasts, I. obliquus showed cytoprotective effects by scavenging intracellular ROS and preventing lipid peroxidation and ultimately stopping premature senescence. Most recently, a significant cognitive enhancement was observed in amnesic mice after orally administration of methanolic extracts of I. obliquus (Giridharan et al., 2011). The critical metabolites responsible for the neuroprotection were thought to be the phenolic ingredients namely 3,4-dihydroxybenzalacetone (76) and caffeic acid (77) (Nakajima et al., 2009) (Supplemental Figure 6). ...
... The passive avoidance test was modified from the earlier reports [19][20][21]. In brief, the apparatus consisted of one clear and one dark chamber, separated by a guillotine door. ...
Mangosteen extracts (ME) contain high levels of polyphenolic compounds and antioxidant activity. Protective effects of ME against β-amyloid peptide (Aβ), induced cytotoxicity have been reported. Here, we further studied the protective effects of ME against oxidative stress induced by hydrogen peroxide (H2O2) and polychlorinated biphenyls (PCBs), and demonstrated the protection against memory impairment in mice. The cytoprotective effects of ME were measured as cell viability and the reduction in ROS activity. In SK-N-SH cell cultures, 200 μg/ml ME could partially antagonize the effects of 150 or 300 µM H2O2 on cell viability, ROS level and caspase-3 activity. At 200, 400 or 800 µg/ml, ME reduced AChE activity of SK-N-SH cells to about 60% of the control. In vivo study, Morris water maze and passive avoidance tests were used to assess the memory of the animals. ME, especially at 100 mg/kg body weight, could improve the animal's memory and also antagonize the effect of scopolamine on memory. The increase in ROS level and caspase-3 activity in the brain of scopolamine-treated mice were antagonized by the ME treatment. The study demonstrated cytoprotective effects of ME against H2O2 and PCB-52 toxicity and having AChE inhibitory effect in cell culture. ME treatment in mice could attenuate scopolamine-induced memory deficit and oxidative stress in brain.
Alcohol‐induced aggression and related violence is a serious and common social problem globally. Alcohol use is increasingly found in the form of alcoholic herbal mixtures (AHM) with indiscriminate and unregulated alcohol content. This study investigated the effects of AHM on aggressive‐like, neurocognitive impairment and brain biochemical alteration in mice. Thirty‐two male resident mice were paired housed with female mice for 21 days in four groups (n = 8). Resident mice were treated orally with normal saline, AHM, ethanol and AHM + ethanol daily for 14 days. Aggressive‐like behaviour was scored based on the latency and frequency of attacks by the resident mouse on the intruder. Neurocognitive impairment was determined using the Y‐maze test (YMT) and novel object recognition test (NORT). Acetylcholinesterase, glutamic acid decarboxylase (GAD), pro‐inflammatory and oxidative stress parameters were determined in the prefrontal cortex (PFC). Neuronal morphology, cytochrome c (Cyt‐c) and nuclear factor‐kappa B (NF‐ĸB) expressions were determined. AHM and in combination with ethanol showed an increased index of aggression typified by frequency of attack and reduced latency to attack when compared to normal saline‐treated animals. Co‐administration of AHM and ethanol significantly reduced cognitive correct alternation (%) and discrimination index in the YMT and NORT, respectively. AHM and ethanol increased acetylcholinesterase, Pro‐inflammatory cytokines and oxidative stress parameters while they reduced GAD. There were significantly reduced neuronal counts and increased expression of Cyt‐c and NF‐ĸB, respectively Alcoholic herbal mixture increased aggressiveness and caused neurocognitive impairment via increased oxido‐inflammatory stress in the prefrontal cortex.
Inonotus obliquus, an edible and medicinal mushroom parasitic on birches, has been used in human diet and for traditional therapies in the high latitude regions of Europe and Asia for a long time. Our phytochemical study of this fungus led to the identification of fourteen triterpenoids including four undescribed ones, and two pairs of undescribed phenolic enantiomers. The undescribed compounds were elucidated by extensive spectroscopic analysis including 1D and 2D NMR and HRESIMS, quantum chemical NMR and ECD calculations, as well as single-crystal X-ray diffraction analysis. Bioassays revealed that eight compounds showed dual inhibition against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) with IC50 values ranging from 2.40 ± 0.05 to 28.72 ± 0.46 μM, while 3β-hydroxy-lanosra-8,24-dien-21-al and trametenolic acid only presented BuChE inhibitory activities with IC50 values of 22.21 ± 1.01 and 7.68 ± 0.13 μM, respectively. In the kinetic studies, the most active three compounds acted as non-competitive inhibitors for both cholinesterases. Furthermore, molecular docking simulations revealed that three compounds demonstrated dual-sites bounding to AChE/BuChE. These triterpenoids emerged as bivalent and dual inhibitors of AChE/BuChE and could be effective drug candidates to prevent and treat Alzheimer's disease in the future.
Dementia including Alzheimer’s disease, is a severe neurodegenerative disorder characterized by progressive cognitive deficits as major symptom. The compositions (BBGS171) including extracts from root of Wongam (a Glycyrriza cultivar), seed of Sorghum bicolor (L.) pupae of Moench and Bombyx mori L. was selected based on preliminary experiments on the ability to improve cognition function in vitro. BBGS171 showed inhibitory activity on cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BuchE) and inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-treated BV2 cells (a microglial cell line). The Y-maze test and passive avoidance test (PAT) were used to evaluate the behavior of an animal model of scopolamine-induced cognitive impairment. Rats administered BBGS171 (EM, extract mixture) in the diet showed better spontaneous alteration and escape latency than those of control rats. Levels of hippocampal choline acetyltransferase (ChAT) and serum acetylcholine (ACh) were significantly higher in the BBGS171 diet group than in the control group. Expression levels of brain-derived neurotrophic factor (BDNF) and extracellular signal-regulated kinase (ERK) 1/2 in the hippocampus of the BBGS171 diet group were also higher than those of control group. These results suggest that BBGS171 (EM) could ameliorate cognition impairment and showed potential as a useful functional material.
Mushrooms have extensively been used not only as a dietary intake but also for the treatment of various central nervous system (CNS) and peripheral nervous system (PNS) disorders. At its early stages, accumulated evidence has suggested that culinary-medicinal mushrooms may play a significant role in the prevention of many age associated neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases. Therefore, further research and efforts have been devoted to a search for more mushroom species that may improve memory and cognitive functions and, in addition, prevent the progression of dementia and neurodegeneration. Such mushrooms include
Hericium erinaceus, Ganoderma lucidum, Lignosus rhinocerotis, Pleurotus giganteus, Sarcodon scabrosus, Antrodia camphorata, Paxillus panuoides, Mycoleptodonoides aitchisonii, and several other species. This review focuses on the various bovementioned neuroprotective, culinary-medicinal mushrooms and the bioactive secondary metabolites isolated from them. The mushrooms’ extracts from basidiocarps/mycelia or isolated compounds have been known to decrease neurotoxicity through various neuroprotective
molecular mechanisms such as anti-acetylcholinesterase activity, neurite outgrowth stimulation (neuritogenic), and nerve growth factor (NGF) synthesis (neurotrophic), enhancing mitochondrial functions and reducing endoplasmic reticulum (ER) stress, in addition to antioxidant and anti-inflammatory effects. Therefore, mushrooms can be considered as useful therapeutic agents in the prevention, management, and/or treatment of neurodegenerative diseases.
This chapter presents an overview of key concepts covered in the subsequent chapters of this book. The book is intended to give an up‐to‐date overview of what is currently known about neurodegenerative diseases, focusing particularly on Alzheimer's disease (AD). Current and developing diagnostic tests are described, and the pathological relationships between AD and other conditions now believed to be risk factors for AD are also described. In particular, the book discusses cardiovascular disease, obesity, insulin resistance and type 2 diabetes, focusing on abnormal lipid and sugar metabolism linked to these conditions, and how this is related to AD risk. It provides evidence that improved diet and exercise may reduce AD risk, not just the risk of the other conditions mentioned above. Hopefully the book provides some food for thought concerning easily adoptable non‐pharmacological methods to reduce AD risk, which would need to be adopted at early pre‐clinical stages of the disease.
Alzheimer’s disease, a progressive neurodegenerative disease, is characterised by hypofunction of acetylcholine (ACh) neurotransmitter in the distinct region of brain. Acetylcholinesterase (AChE) is an enzyme that metabolises the ACh at synaptic cleft resulting in Alzheimer’s disease. Medicinal plants have been used to treat numerous ailments and improve human health from ancient time. A traditional system of medicine is long recognised for its effective management of neurological disorders. The present review confers the scope of some common medicinal plants with a special focus on AChE-mediated central nervous system complications especially Alzheimer’s disease. Literature suggests that medicinal plants reduce neuronal dysfunctions by reducing AChE activity in different brain regions. In some instances, activation of AChE activity by medicinal plants also showed therapeutic potential. In conclusion, medicinal plants have a wide scope and possess therapeutic potential to efficiently manage neurological disorders associated with AChE dysregulation.
Inonotus obliquus, commonly known as chaga, is a basidiomycetous wood-decaying fungus from Hymenochaetaceae family, growing usually on birch trees. Since the sixteenth century, chaga has been used as a folk medicine in Russia and Northern Europe, mainly for cancer and tuberculosis treatment. Many bioactive compounds were isolated from chaga mushroom, especially polysaccharides, triterpenes and steroids. Nowadays it is used throughout the world and many studies confirm its medicinal effects: anti-tumor, antioxidant, antiinflammatory, hepatoprotective, antimicrobial, immunomodulatory and antidiabetic.
The profile of caffeic acid in tissues of peanut sprouts and its antioxidant activity in erythrocyte-based assays were investigated. Caffeic acid was found to accumulate in the epicotyl-plumule (reached 2097.13 ± 96 μg/g DW on day 10 after peanut germination). It was purified by semipreparative high-performance liquid chromatography. The purified caffeic acid showed noticeable protective effects on human erythrocytes against 2,2′-azobis-(2-amidinopropane) dihydrochloride (AAPH)-induced hemolysis. It also contributed to maintenance of normal morphological features and inhibited malondialdehyde formation and the lactate dehydrogenase release in erythrocytes under oxidative stress. Further analysis revealed that caffeic acid effectively inhibited AAPH-induced free-radical production and maintained the normal metabolism of the erythrocytic redox system, including superoxide dismutase, glutathione peroxidase, and glutathione. Our work showed that caffeic acid, which is greatly enriched in peanut sprout, can effectively protect erythrocytes from oxidative damage. These results provide valuable information for the use of peanut sprouts as a functional food.
The present study reports the effect of amide derivatives of 1,3,4-thiadizoles on scopolamine induced deficit cholinergic neurotransmission and oxidative stress serving as promising leads for the therapeutics of cognitive dysfunction. Fourteen compounds (2c–8d) have been synthesised and evaluated against behavioural alterations using step down passive avoidance protocol and morris water maze and at a dose of 0.5 mg/kg with reference to the standard, Rivastigmine. All the synthesised compounds were evaluated for their in vitro acetylcholinesterase (AChE) inhibition at five different concentrations using mice brain homogenate as the source of the enzyme. Biochemical estimation of markers of oxidative stress (lipid peroxidation, superoxide dismutase, glutathione, plasma nitrite, catalase) has also been carried out to assess the role of synthesised molecules on the oxidative damage induced by scopolamine. The compounds 5c, 6c and 8c displayed appreciable activity with an IC50 value of 3 μM, 3.033 μM and 2.743 μM, respectively towards acetylcholinesterase inhibition. These compounds also decreased scopolamine induced oxidative stress, thus serving as promising leads for the amelioration of oxidative stress induced cognitive decline. The molecular docking study performed to predict the binding mode of the compounds also suggested that these compounds bind appreciably with the amino acids present in the active site of recombinant human acetylcholinesterase (rhAChE). The results indicated that these compounds could be further traversed as inhibitors of AChE and oxidative stress for the treatment of cognitive dysfunction.
Abstract Mushrooms have long been used not only as food but also for the treatment of various ailments. Although at its infancy, accumulated evidence suggested that culinary-medicinal mushrooms may play an important role in the prevention of many age-associated neurological dysfunctions, including Alzheimer's and Parkinson's diseases. Therefore, efforts have been devoted to a search for more mushroom species that may improve memory and cognition functions. Such mushrooms include Hericium erinaceus, Ganoderma lucidum, Sarcodon spp., Antrodia camphorata, Pleurotus giganteus, Lignosus rhinocerotis, Grifola frondosa, and many more. Here, we review over 20 different brain-improving culinary-medicinal mushrooms and at least 80 different bioactive secondary metabolites isolated from them. The mushrooms (either extracts from basidiocarps/mycelia or isolated compounds) reduced beta amyloid-induced neurotoxicity and had anti-acetylcholinesterase, neurite outgrowth stimulation, nerve growth factor (NGF) synthesis, neuroprotective, antioxidant, and anti-(neuro)inflammatory effects. The in vitro and in vivo studies on the molecular mechanisms responsible for the bioactive effects of mushrooms are also discussed. Mushrooms can be considered as useful therapeutic agents in the management and/or treatment of neurodegeneration diseases. However, this review focuses on in vitro evidence and clinical trials with humans are needed.
We isolated 2,3-dihydroxy-4-methoxyacetophenone, a neuroprotective compound from Cynenchum paniculatum in our previous study. The present study was conducted to investigate the possible neuroprotective effect of 2,3-dihydroxy-4-methoxyacetophenone that has been previously isolated from Cynenchum paniculatum on hippocampal neuronal cell line, HT22 cells and its possible cognitive-enhancing effect on scopolamine-induced amnesia in mice. Neuroprotective effect against glutamate-induced neurotoxicity in HT22 cells was evaluated by MTT assay. Also, cognitive enhancing effect against scopolamine (1mg/kg, ip) induced learning and memory deficit was measured by Morris water maze test. Oral administered of 2,3-dihydroxy-4-methoxyacetophenone (1, 10, 20, 40 and 50mg/kg) to amnesic mice induced by scopolamine. In Morris water maze test, 2,3-dihydroxy-4-methoxyacetophenone (50mg/kg) improved the impairment of spatial memory induced by scopolamine. 2,3-Dihydroxy-4-methoxyacetophenone protect HT22 cells on glutamate induced cell-death in a dose-dependent manner (EC50 value: 10.94μM). Furthermore, 2,3-dihydroxy-4-methoxyacetophenone was found to inhibit [Ca(2+)] accumulation in HT22 cells and had antioxidantive activity. The results showed that 2,3-dihydroxy-4-methoxyacetophenone exert neuroprotective and cognitive-enhancing activities through its antioxidant activity. We suggest that 2,3-dihydroxy-4-methoxyacetophenone improves cognitive function and may be helpful for the treatment of Alzheimer's disease.
Glaucocalyxin (Gla) A-C are major ent-kauranoid diterpenoids isolated from Rabdosia japonica var. glaucocalyx, a plant used in Chinese traditional medicine as antitumor and anti-inflammatory agents. The present investigation was carried out to observe whether cellular reduced glutathione (GSH) plays important roles in Gla -induced cytotoxicity. Among major ent-kauranoid diterpenoids isolated, Gla A and B dose-dependently decreased the growth of HL-60 cells with an IC50 of approximately 6.15 and 5.86 μM at 24 h, respectively. Both Gla A and B could induce apoptosis, G2/M-phase cycle arrest, DNA damage and the accumulation of reactive oxygen species (ROS) in HL-60 cells. Moreover, Gla A, B caused rapidly decrease of the intracellular GSH content, while inhibition of cellular GSH synthesis by buthionine sulfoximine (BSO) augmented the induced cytotoxicity and apoptosis in HL-60 cells. On the other hand, the administration of GSH or GSH precursor N-acetyl-cysteine (NAC) could rescue Gla A, B-depleted cellular GSH, and abrogate the induced cytotoxicity, G2/M-phase cycle arrest, DNA damage and ROS accumulation in HL-60 cells. Furthermore, Gla A, B decreased the activity of the GSH-related enzymes including glutathione reductase (GR) and glutathione peroxidase (GPX). These data suggest that the intracellular GSH redox system plays important roles in regulating the Gla A, B-induced cytotoxicity on HL-60 cells.
The effect of α-asarone on impairment of cognitive performance caused by amnesic drug scopolamine was investigated. Treatment with α-asarone attenuated scopolamine-induced cognitive deficits as evaluated by passive avoidance and Y-maze test. Administration of α-asarone for 15 d improved memory and cognitive function as indicated by an increase in transfer latency time and spontaneous alternation in passive avoidance and the Y-maze test respectively. To understand the action of α-asarone, the levels of acetylcholinesterase (AChE), malondialdehyde (MDA), and superoxide dismutase (SOD) in the hippocampus (Hippo) and cerebral cortex (CC) of scopolamine-induced amnesic mice were evaluated. The mice treated with Scopolamine showed increased activity of AChE, MDA and SOD levels in both the Hippo and the CC area. Treatment with α-asarone attenuated the increased activity of AChE and normalized the MDA and SOD levels in the Hippo and the CC area in the scopolamine treated amnesic mice. These results suggest that α-asarone has a beneficial effect in cognitive impairment induced by dysfunction of cholinergic system in brain through inhibition of AChE activity and by influencing the antioxidant defense mechanism.
White button mushroom extract was examined in this study on (1) its potential effect on angiogenesis in chorioallantoic culture and (2) its recovering effect on the skin after injury in the ICR mice. Methods used included TUNEL assay on apoptosis, immunohistochemistry for vascular endothelial growth factor (VEGF), proliferative cell nuclear antigen (PCNA), epidermal growth factor (EGF), transforming growth factor β (TGF-β), and immune factor CD4 and western blotting. The results of chorioallantoic culture showed that the mushroom treatment led to significant increase in densities of VEGF sites. In the skin injury, ICR mice model increased EGF, PCNA, and collagen fibers, along with decrease of TUNEL positive apoptotic cells and limited reaction of TGF-β and CD4 indicated that white button mushroom extract appeared to have beneficial effects on skin in regeneration and after injury. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
Alzheimer's disease (AD) is characterized by signs of major oxidative stress and the loss of cholinergic cells. The present study was designed to investigate the role of the total alkaloidal extract from Murraya koenigii (MKA) leaves on age related oxidative stress and the cholinergic pathway in aged mice. Ascorbic acid (100 mg/kg, p.o.) was used as a standard drug. The MKA improved the level of protective antioxidants such as glutathione peroxidase (GPx), reduced glutathione (GSH), glutathione reductase (GRD), superoxide dismutase (SOD) and catalase (CAT) in brain homogenate at higher doses (20 and 40 mg/kg, p.o.). Moreover, a dose dependent decline was noted in lipid peroxidation (LPO) and the nitric oxide assay (NO) at all doses of MKA (10, 20 and 40 mg/kg, p.o.). Interestingly, significant progress was noted with the supplementation of MKA by an improvement of the acetylcholine (ACh) levels and a reduction in the acetylcholinesterase (AChE) activity in aged mouse brain. In addition, a significant elevation of serum albumin (ALBU), alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and total protein as well as a decline in creatinine, total cholesterol, urea nitrogen and glucose levels with MKA also ameliorated the hepatic and renal functions in normal ageing process. The results showed the possible utility of Murraya koenigii leaves in neuroprotection against neurodegenerative disorders such as Alzheimer's disease. Copyright © 2012 John Wiley & Sons, Ltd.
A total of 28 male BALB/c mice (average weight 20.7 +/- 1.6 g) were divided into 4 treatment groups and fed a commercial diet (A), a commercial diet + induced colitis by dextran sodium sulfate (DSS) (B), Inonotus obliquus (IO) administration (C), and IO administration + induced colitis by DSS (D). IO treatment (C, D) decreased the expression of tumor necrosis factor (TNF)-alpha and signal transducers and activators of transcription (STAT)1 compared to those of the colitis induced group (B). The expressions of IL-4 and STAT6 were decreased in group D compared to the colitis induced group (B). The serum immunoglobulin (Ig)E level decreased in IO treatment groups (C, D) compared to no IO treatment groups (A and B) although there was no significant difference between the IO treatment groups. Extract from IO itself had a weak cytotoxic effect on murine macrophage cell line (RAW264.7 cells). Extract from IO inhibited lipopolysaccharide- (LPS-) induced, TNF-alpha, STAT1, pSTAT1, STAT6, and pSTAT6 production in RAW264.7 cells.
Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine (ACh) level in the cerebral cortex and hippocampus of rats and Mongolian gerbils were examined. In normal rats, MCI-2016 (30 mg/kg, i.p.) slightly increased ACh content in the cerebral cortex. Scopolamine (1 mg/kg, i.p.) or hypoxia (95% N2 +5% O2, 9 min) decreased ACh level and pretreatment of MCI-2016 attenuated the decrement of ACh level in the rats. ACh level in the brain of Mongolian gerbils was significantly decreased following ligation of bilateral carotid arteries. In this case, MCI-2016 also attenuated the decrement of ACh level. These results suggest that improvement by MCI-2016 of behavioral impairment observed in the animals treated with scopolamine, hypoxia or ischemia may be, at least partly, attributed to the amelioration of decreased ACh level in the brain.
A new automated system for the analysis of nitrate via reduction with a high-pressure cadmium column is described. Samples of urine, saliva, deproteinized plasma, gastric juice, and milk can be analyzed for nitrate, nitrite, or both with a lower limit of detection of 1.0 nmol NO3− or NO2−/ml. The system allows quantitative reduction of nitrate and automatically eliminates interference from other compounds normally present in urine and other biological fluids. Analysis rate is 30 samples per hour, with preparation for most samples limited to simple dilution with distilled water. The application of gas chromatography/mass spectrometry for the analysis of 15NO3− in urine after derivatization to 15NO2-benzene is also described.
Since the idea that memory is associated with alterations in synaptic strength was accepted, studies on the cellular and molecular mechanisms responsible for the plastic changes in neurons have attracted wide interest in the scientific community. Recent studies on memory processes have also pointed out some unifying themes emerging from a wide range of nervous systems, suggesting that regardless of the species or brain regions, a common denominator for memory may exist. Thus, the present review attempted to create a hypothetical and universal synaptic model valid for a variety of nervous systems, ranging from molluscs to mammals. The cellular and molecular events leading to short- and long-term modifications of memory have been described in a sequential order, from the triggering signals to the gene expression, synthesis of new proteins and neuronal growth. These events are thought to represent the late phases of memory consolidation leading to persistent modifications in synaptic plasticity, thereby facilitating the permanent storage of acquired information throughout the individual's life.
Glutathione (GSH) is an important intracellular peptide with multiple functions ranging from antioxidant defense to modulation of cell proliferation. GSH is synthesized in the cytosol of all mammalian cells in a tightly regulated manner. The major determinants of GSH synthesis are the availability of cysteine, the sulfur amino acid precursor, and the activity of the rate-limiting enzyme, gamma-glutamylcysteine synthetase (GCS). In the liver, major factors that determine the availability of cysteine are diet, membrane transport activities of the three sulfur amino acids cysteine, cystine and methionine, and the conversion of methionine to cysteine via the trans-sulfuration pathway. Many conditions alter GSH level via changes in GCS activity and GCS gene expression. These include oxidative stress, activators of Phase II detoxifying enzymes, antioxidants, drug-resistant tumor cell lines, hormones, cell proliferation, and diabetes mellitus. Since the molecular cloning of GCS, much has been learned about the regulation of this enzyme. Both transcriptional and post-transcriptional mechanisms modulate the activity of this critical cellular enzyme.--Lu, S. C. Regulation of hepatic glutathione synthesis: current concepts and controversies.
Oxidative stress has been implicated in cognitive impairment in both old experimental animals and aged humans. This implication has led to the notion that antioxidant defense mechanisms in the brain are not sufficient to prevent age-related increase in oxidative damage and that dietary intake of a variety of antioxidants might be beneficial for preserving brain function. Here we report a dramatic loss of learning and memory function from 8 to 11 months of age in mice, associated with marked increases in several markers of brain oxidative stress. Chronic systemic administration of two synthetic catalytic scavengers of reactive oxygen species, Eukarion experimental compounds EUK-189 and EUK-207, from 8 to 11 months almost completely reversed cognitive deficits and increase in oxidative stress taking place during this time period in brain. In particular, increase in protein oxidation was completely prevented, whereas increase in lipid peroxidation was decreased by approximately 50%. In addition, we observed a significant negative correlation between contextual fear learning and levels of protein oxidation in brain. These results further support the role of reactive oxygen species in age-related learning impairment and suggest potential clinical applications for synthetic catalytic scavengers of reactive oxygen species.
The cholinergic hypothesis of decline in dementia, whereby deficits in learning, memory and behavior are caused, at least in part, by decreased levels of acetylcholine (ACh) in the brain, first emerged more than 20 years ago. The role for acetylcholinesterase (AChE) and its inhibition in this scheme has long been accepted, but findings from preclinical experiments and clinical trials have placed butyrylcholinesterase (BuChE) alongside AChE as an important contributor to the occurrence, symptoms, progression and responses to treatment in dementia. A number of new lines of evidence suggest that both cholinesterase inhibitors (ChEs) may have broader functions in the CNS than previously thought, which relate to both 'classical' esterase activities of the enzymes as well as non-classical actions unrelated to their enzymatic function. Data suggest involvement of the ChEs in modulating glial activation, cerebral blood flow, the amyloid cascade, and tau phosphorylation. It has therefore been speculated that some actions of the ChEs could affect the underlying disease processes in Alzheimer's disease (AD), and that pharmacological manipulation with ChE inhibitors may affect long-term disease progression. Focusing on new findings relating to BuChE, we review recent evidence that has extended knowledge into the roles of ChEs in health, disease and aging.
Alzheimer's disease (AD) is associated with a loss of cholinergic neurons resulting in profound memory disturbances and irreversible
impairment of cognitive function. The central cholinergic system is involved in the action of general anaesthetic agents.
Anaesthetic modulation of cholinergic transmission has profound effects on brain function via a cascade of synaptic and postsynaptic events by binding both nicotinic and muscarinic receptors. During general anaesthesia,
decrease in acetylcholine release and depression of cholinergic transmission facilitates the desirable effects of general
anaesthetics, such as loss of consciousness, pain, voluntary movements and memory. From this point of view, patients with
AD, characterized by a compromised neuronal transmission, represent particular cases in which the choice of anaesthesia drugs
may have a negative effect on the postoperative outcome. A future challenge may be the identification of brain targets of
general anaesthetics which do not expose patients to postoperative cognitive dysfunction, nor interfere with prognosis of
brain degenerative disease.
Inonotus obliquus (persoon) Pilat (Chaga, in Russia, kabanoanatake in Japan) is a fungus having been used as a folk medicine in Russia and said to have many health beneficial functions such as immune modulating and anti-cancer activities. In the present study, the antioxidant activity of hot water extract (decoction) of Chaga was precisely compared with those of other medicinal fungi (Agaricus blazei Mycelia, Ganoderma lucidum and Phellinus linteus) showing Chaga had the strongest antioxidant activity among fungi examined in terms of both superoxide and hydroxyl radicals scavenging activities. Further determination of the antioxidant potential of isolated fruiting body (brown part) and Sclerotium (black part) revealed the 80% MeOH extract of fruiting body had the highest potential as high as that of Chaga decoction. Finally, seven antioxidant components were isolated and purified from the 80% MeOH extract of Chaga fruiting body, and their chemical structures were determined as small phenolics as follows: 4-hydroxy-3,5-dimethoxy benzoic acid 2-hydroxy-1-hydroxymethyl ethyl ester (BAEE), protocatechic acid (PCA), caffeic acid (CA), 3,4-dihybenzaladehyde (DB), 2,5-dihydroxyterephtalic acid (DTA), syringic acid (SA) and 3,4-dihydroxybenzalacetone (DBL). Notably, BAEE was assigned as the new compound firstly identified from the natural source in the present study.
Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer's disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA-DNA and DNA-protein cross-linking, and formation of at least 20 modified bases adducts. In addition, alpha,beta-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage AD (LAD) brain show elevations of 8-hydroxyguanine (8-OHG), 8-hydroxyadenine (8-OHA), 5-hydroxycytosine (5-OHC), and 5-hydroxyuracil, a chemical degradation product of cytosine, in both nuclear and mitochondrial DNA (mtDNA) isolated from vulnerable regions of LAD brain compared to age-matched normal control subjects. Previous studies also show elevations of acrolein/guanine adducts in the hippocampus of LAD subjects compared to age-matched controls. In addition, studies of base excision repair show a decline in repair of 8-OHG in vulnerable regions of LAD brain. Our recent studies show elevated 8-OHG, 8-OHA, and 5,6-diamino-5-formamidopyrimidine in both nuclear and mtDNA isolated from vulnerable brain regions in amnestic mild cognitive impairment, the earliest clinical manifestation of AD, suggesting that oxidative DNA damage is an early event in AD and is not merely a secondary phenomenon.
In recent years, oxidative stress has been implicated in a variety of degenerative processes, diseases, and syndromes. Some of these include atherosclerosis, myocardial infarction, stroke, and ischemia/reperfusion injury; chronic and acute inflammatory conditions such as wound healing; central nervous system disorders such as forms of familial amyotrophic lateral sclerosis (ALS) and glutathione peroxidase-linked adolescent seizures; Parkinson’s disease and Alzheimer’s dementia; and a variety of other age-related disorders. Among the various biochemical events associated with these conditions, emerging evidence suggests the formation of superoxide anion and expression/activity of its endogenous scavenger, superoxide dismutase (SOD), as a common denominator. This review summarizes the function of SOD under normal physiological conditions as well as its role in the cellular and molecular mechanisms underlying oxidative tissue damage and neurological abnormalities. Experimental evidence from laboratory animals that either overexpress (transgenics) or are deficient (knockouts) in antioxidant enzyme/protein levels and the genetic SOD mutations observed in some familial cases of ALS are also discussed.
Chronic treatment of adult male F-344 rats (9–12 months old) with therapeutically relevant doses of memantine (30 mg/kg/day in chow for <8 weeks) increased the maintenance of long-term potentiation of field excitatory postsynaptic potentials from perforant path—granule cell hippocampal synapses recorded in the fascia dentata in vivo. In contrast, there was no effect of memantine on baseline synaptic responses or population spikes. Likewise, short-term exploratory modulation of these hippocampal evoked responses was not different between memantine-treated and control rats. Both groups of rats were able to learn the spatial version of the Morris water task equally well, but the memantine-treated group showed a strong tendency to show more selective spatial search patterns in the training quadrant of the water pool during a final probe trial. As such, these studies provide the first electrophysiological evidence that memantine can increase the durability of synaptic plasticity and provide preclinical confirmation of the cognitive improvement seen with memantine in the treatment of demented patients.
Data on the chemical composition and pharmacological activity of chaga (Inonotus obliquus) are reviewed. The possible mechanisms of action and factors responsible for the discrepancy of data available in the literature
are discussed. The physical and chemical characteristics of melanin (polyphenolic chromogenic humin-like complex present in
chaga) and its role in the regulation of physiological processes are considered.
A photometric method for determining acetylcholinesterase activity of tissue extracts, homogenates, cell suspensions, etc., has been described. The enzyme activity is measured by following the increase of yellow color produced from thiocholine when it reacts with dithiobisnitrobenzoate ion. It is based on coupling of these reactions: The latter reaction is rapid and the assay is sensitive (i.e. a 10 μ1 sample of blood is adequate). The use of a recorder has been most helpful, but is not essential. The method has been used to study the enzyme in human erythrocytes and homogenates of rat brain, kidney, lungs, liver and muscle tissue. Kinetic constants determined by this system for erythrocyte eholinesterase are presented. The data obtained with acetylthiocholine as substrate are similar to those with acetylcholine.
The ethanolic crude extracts and three subfractions (ethyl acetate fraction, n-butanol fraction, and aqueous fraction) from Inonotus Obliquus were obtained by sequential partitioning and their antioxidant activities were investigated in the present study. The methods of the total antioxidant capacity measured by the ferric-reducing antioxidant power assay, reducing power assay, scavenging activities towards DPPH, superoxide anion and hydroxyl radical employed in this study were established in in vitro systems. The amounts of total phenolics and total flavonoids were also determined by spectrophotometer. The results showed that the crude extracts and subfractions exhibited antioxidant activities in different evaluating system. The decreasing order of antioxidant activities is ethyl acetate fraction >n-butanol fraction >crude extract>aqueous fraction. A similar order of the amounts of phenolics and flavonoids in extract and subfractions was found. The results showed that the extent of antioxidant activities is in accordance with the amounts of phenolics and flavonoids existing in extracts and subfractions.
The preventive effect of schisandrin B (Sch B), an antioxidant ingredient of Schisandra chinensis, was studied on scopolamine-induced dementia in mouse. Scopolamine developed oxidative stress in the brain with the decreased levels of antioxidant enzymes and increased nitrite level. At the same time, a significant impairment of learning and memory occurred when evaluated by passive avoidance task (PAT) and Morris water maze (MWM) with concomitant increase of acetylcholinesterase (AChE) activity and decreased acetylcholine levels. Pre-treatment by Sch B (10, 25, 50 mg/kg) effectively prevented scopolamine-induced oxidative stress and improved behavioural tasks. Further, the scopolamine-induced increase in AChE activity was significantly suppressed and the level of acetylcholine was maintained as normal by Sch B treatment. These results suggest that Sch B have protective function against cerebral functional defects such as dementia not only by antioxidant prevention but also exerting its potent cognitive-enhancing activity through modulation of acetylcholine level.
In this study, we investigated the immunostimulating activity of polysaccharides isolated from fruiting body of Inonotus obliquus (PFIO). Additionally, the signaling pathway of PFIO-mediated macrophage activation was investigated in RAW264.7 macrophage cells. We found that PFIO was capable of promoting NO/ROS production, TNF-α secretion and phagocytic uptake in macrophages, as well as cell proliferation, comitogenic effect and IFN-γ/IL-4 secretion in mouse splenocytes. PFIO was able to induce the phosphorylation of three MAPKs as well as the nuclear translocation of NF-κB, resulting in activation of RAW264.7 macrophages. PFIO also induced the inhibition of TNF-α secretion by anti-TLR2 mAb, consequently, PFIO might be involved in TNF-α secretion via the TLR2 receptor. In addition, our results showed that oral administration of PFIO suppressed in vivo growth of melanoma tumor in tumorbearing mice. In conclusion, our experiments presented that PFIO effectively promotes macrophage activation through the MAPK and NF-κB signaling pathways, suggesting that PFIO may potentially regulate the immune response.
The inhibitory effects of inotilone and methylinotilone on the induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in murine RAW 264.7 cells activated with LPS were investigated. The results show that both hydroxyl groups on the benzene ring of the inotilone molecule are required for better anti-inflammatory effect. Western blotting and RT-PCR analyses demonstrated that inotilone blocked protein and mRNA expression of iNOS but not COX-2. Instead, inotilone inhibited prostaglandin E(2) production through decreasing the enzyme activity of COX-2. The repression of iNOS but not COX-2 expression may come from the differential effect of inotilone on nuclear factor-kappaB (NFkappaB) and CCAAT/enhancer-binding protein beta Treatment with inotilone resulted in the reduction of LPS-induced nuclear translocation of NFkappaB subunit and the NFkappaB-dependent transcriptional activity by blocking phosphorylation of inhibitor kappaB(IkappaB)alpha and p65 and subsequent degradation of inhibitor kappaBalpha. Inotilone also inhibited LPS-induced activation of PI3K/Akt and extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase. Our results suggest that inotilone may have potential to be developed into an effective anti-inflammatory agent.
Chaga (Inonotus obliquus (persoon) Pilat) is a mushroom traditionally used as a folk medicine for tumors and stomach ulcers in Russia. Previously, we reported the antioxidant potential of Chaga extracts and seven isolated phenolic ingredients. In the present study, we investigated the protective effects of Chaga extracts and other isolated phenolic ingredients against H(2)O(2)-induced oxidative stress in PC12 cells. Intracellular generation of reactive oxygen species (ROS) leads to oxidative stress and subsequent damage of cellular and nuclear components. Chaga extracts and the phenolic ingredients, 3,4-dihydroxybenzalacetone (DBL) and caffeic acid (CA), effectively suppressed intracellular ROS level in H(2)O(2)-treated cells. The H(2)O(2)-induced cell death was more pronounced, effectively prevented in the cells treated with DBL than in cells treated with CA. In addition, ROS activate various signal transduction pathways including the mitogen-activated protein kinase (MAPK) cascade. Therefore, we examined the potentially beneficial effects of DBL on extracellular signal-regulated protein kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38-MAPK signaling activated by H(2)O(2) stimulation. DBL selectively inhibited the phosphorylation of p38-MAPK, without affecting JNK and ERK.
The aim of this study was to evaluate the effects of Anemarrhena asphodeloides BUNGE (AA) on cholinergic memory deficits in mice. This agent has previously been used as an antipyretic, anti-inflammatory, anti-diabetic, and antidepressant in traditional Chinese medicine. Mangiferin was isolated from AA and showed a dose-dependent inhibition of acetylcholinesterase (AChE) activity (IC(50) value, 62.8 microM). Cholinergic dysfunction was induced in mice by administering scopolamine, and the animals were then tested using the passive avoidance test as well as the Morris water maze test. Mangiferin (20 mg/kg, p.o.) significantly reversed scopolamine-induced deficits in the passive avoidance test, and also improved escape latencies in training trials and increased swimming times in the Morris water maze test (p<0.05). Mangiferin also reduced acetylcholine and tumor necrosis factor (TNF)-alpha levels induced by scopolamine in mice brain (p<0.05) and inhibited nuclear factor (NF)-kappaB activation in scopolamine or TNF-alpha-stimulated BV-2 microglial cells. These results suggest that mangiferin can improve long-term cholinergic memory deficits by AChE inhibition or cholinergic receptor stimulation and inhibition of NF-kappaB activation.
The reaction of lipid peroxides in animal tissues with thiobarbituric acid was dependent on pH of the reaction mixture as was the case for linoleic acid hydroperoxide. The optimum pH was found to be 3.5. Taking this fact into consideration, a standard procedure for the assay of lipid peroxide level in animal tissues by their reaction with thiobarbituric acid was developed as follows. Ten percent ( tissue homogenate was mixed with sodium dodecyl sulfate, acetate buffer (pH 3.5), and aqueous solution of thiobarbituric acid. After heating at 95°C for 60 min, the red pigment produced was extracted with n-butanol-pyridine mixture and estimated by the absorbance at 532nm. As an external standard, tetramethoxy-propane was used, and lipid peroxide level was expressed in terms of nmol malondialdehyde. Using this method, the liped peroxide level in the liver of rats suffering from carbon tetrachloride intoxication was investigated. The results were in good agreement with previously reported data obtained by measuring diene content.
Scopolamine produces a satisfactory model of the attentional and secondary memory deficits seen in Alzheimer's disease (AD) that can be used to screen compounds for potential therapeutic usefulness. Physostigmine, which is known to enhance memory in AD, produced marked and widespread antagonism of the scopolamine-induced impairments, indicating the sensitivity of the model and establishing its relevance for the clinical situation. HP 029, a novel anticholinesterase, also exhibited widespread potency in the model, and in an international trial with patients with AD, it subsequently showed improvement on similar measures, demonstrating the predictive use of the scopolamine model.
D-Cycloserine is a partial agonist at the strychnine-insensitive neuronal glycine receptor and positively modulates the N-methyl-D-aspartate (NMDA) excitatory amino acid receptor. NMDA receptors appear to be important in learning and memory, and D-cycloserine facilitates learning in rats. In man, central cholinergic blockade due to scopolamine administration impairs attention, information processing, and memory for new information, the latter secondary memory impairments resembling those shown in patients with Alzheimer's disease (AD). D-Cycloserine has been studied for its ability to counteract the cognitive decrements produced by scopolamine in young and elderly healthy volunteers. D-Cycloserine specifically antagonized the memory impairments produced by scopolamine. These findings provide evidence of NMDA receptor involvement in human memory and suggest a novel mechanism for alleviation of memory loss associated with aging and dementia.
Growth medium of Inonotus obliquus exerts antimitotic effect on HeLa cells mostly in M, G1 and G2 phases increasing at the same time catalase activity. This effect was not observed in prokaryotic Nocardia. Significant antimitotic effect of mycelium was not associated with stimulation of catalase activity in HeLa cells.
Free radicals are found to be involved in both initiation and promotion of multistage carcinogenesis. These highly reactive compounds can act as initiators and/or promoters, cause DNA damage, activate procarcinogens, and alter the cellular antioxidant defense system. Antioxidants, the free radical scavengers, however, are shown to be anticarcinogens. They function as the inhibitors at both initiation and promotion/transformation stage of carcinogenesis and protect cells against oxidative damage. Altered antioxidant enzymes were observed during carcinogenesis or in tumors. When compared to their appropriate normal cell counterparts, tumor cells are always low in manganese superoxide dismutase activity, usually low in copper and zinc superoxide dismutase activity and almost always low in catalase activity. Glutathione peroxidase and glutathione reductase activities are highly variable. In contrast, glutathione S-transferase 7-7 is increased in many tumor cells and in chemically induced preneoplastic rat hepatocyte nodules. Increased glucose-6-phosphate dehydrogenase activity is also found in many tumors. Comprehensive data on free radicals, antioxidant enzymes, and carcinogenesis are reviewed. The role of antioxidant enzymes in carcinogenesis is discussed.
The total glutathione content of biological samples is conveniently determined with an enzymatic recycling assay based on glutathione reductase (F. Tietze, 1969, Anal. Biochem.27, 502–522). In the original and several subsequent descriptions of this procedure, glutathione disulfide is selectively determined by assaying samples in which glutathione is masked by pretreatment with N-ethylmaleimide. Since N-ethylmaleimide is a potent inhibitor of glutathione reductase, it is necessary to remove excess reagent; the procedures used are laborious and contribute significantly to experimental error. It is reported here that 2-vinylpyridine is a much better reagent for the derivitization of glutathione. In contrast to N-ethylmaleimide, 2-vinylpyridine does not inhibit glutathione reductase significantly and therefore need not be removed from the sample solutions. 2-Vinylpyridine reacts with glutathione at slightly acidic pH values where spontaneous formation of glutathione disulfide is minimal. It is demonstrated that the total glutathione concentration in mouse plasma is substantially higher than generally reported and that glutathione disulfide constitutes less than 30% of the total glutathione present.
Point mutations in the cytosolic Cu/Zn superoxide dismutase (SOD-1) gene have been detected in association with familial amyotrophic lateral sclerosis (FALS). SOD clears superoxide radical and is one of the body's principal defense mechanisms against oxygen toxicity. The finding of SOD variants in FALS is consistent with the hypothesis that free radicals contribute to the pathogenesis of FALS, and possibly to the pathogenesis of other neurodegenerative disorders such as Parkinson's disease, in which there is substantial evidence of oxidant stress. The implication of free radicals in the pathogenesis of neurodegenerative disorders raises the possibility that antioxidants might provide neuroprotective therapy.
The potential of heptylphysostigmine tartrate (pyrrolo [2,3b] indol-5-ol, 3,3a,8,8a-hexahydro-1,3a,8-trimethylheptylcarbamate [ester, (3aS-cis)]) (MF201), a new second-generation cholinesterase inhibitor, to antagonize scopolamine-induced amnesia in rats was assessed in an 8-arm radial maze. Upon completing the training session, the rats were orally administered increasing doses of MF201 (2, 3, 4, 6 and 8 mg/kg) 60 min prior to a s.c. injection of scopolamine (0.25 mg/kg). 9-Amino-1,2,3,4-tetrahydroamino-acridine hydrochloride hydrate (tacrine) (0.25, 0.37, 0.5, 1 and 2 mg/kg), 1-benzil-4-[(5,6-dimethoxy-1-indanon)-2-yl]-methyl piperidine (E2020) (0.125, 0.18, 0.25 and 0.5 mg/kg) and physostigmine (0.15, 0.25, 0.5 and 1 mg/kg) were orally administered and rats were tested in the same task. As previously described, scopolamine induced an impairment in radial maze performance, measured in terms of total number of errors, total time taken to complete the task and the percentage of amnesic animals. The reversal of scopolamine-induced impairment was characterized by the presence of an inverted U-shaped dose-response curve. A significant antagonistic effect was achieved with a dose (mg/kg) of 0.25 for E2020, 0.5 for tacrine and physostigmine and 3, 4 and 6 for MF201, the latter manifesting a broader spectrum of activity (3-6 mg/kg). While the maximal active doses restored the scopolamine-induced modified pattern of arm entry, they were ineffective in reducing hypermotility, suggesting the drugs have a specific effect on cognitive function.
The cholinergic hypothesis claims that the decline in cognitive functions in dementia is predominantly related to a decrease in cholinergic neurotransmission. This hypothesis has led to great interest in the putative involvement of the cholinergic neurotransmission in learning and memory processes. This review aims to assess the data of studies in which the role of acetylcholine (ACh) in cognitive functions was investigated. For this purpose, studies from three different fields of research, namely: (1) behavioral pharmacology (effects of drugs on behavior); (2) behavioral neuroscience (effects of brain lesions on behavior); and (3) dementia, are discussed separately. The experimental tools that have been used in pharmacological studies may appear to be inadequate to enable conclusions to be drawn about the involvement of ACh in learning and memory processes. Especially, the use of scopolamine as a pharmacological tool is criticized. In the field of behavioral neuroscience a highly specific cholinergic toxin has been developed. It appears that the greater and more specific the cholinergic damage, the fewer effects can be observed at the behavioral level. The correlation between the decrease in cholinergic markers and the cognitive decline in dementia may not be as clearcut as has been assumed. The involvement of other neurotransmitter systems in cognitive functions is briefly discussed. Taking into account the results of the different fields of research, the notion that ACh plays a pivotal role in learning and memory processes seems to be overstated. Even when the role of other neurotransmitter systems in learning and memory is taken into consideration, it is unlikely that ACh has a specific role in these processes. On basis of the available data, ACh seems to be more specifically involved in attentional processes than in learning and memory processes.
D-Cycloserine, a partial agonist at the glycine binding site on the NMDA receptor/channel complex, did not affect the number of errors (attempts to pass through two incorrect panels of the three-panel gates at four choice points) in the working memory task with a three-panel runway setup, when injected bilaterally at 1 or 10 microg/side into the dorsal hippocampus. Intrahippocampal administration of the muscarinic receptor antagonist scopolamine (3.2 microg/side) significantly increased the number of working memory errors. The increase in working memory errors induced by intrahippocampal 3.2 microg/side scopolamine was significantly reduced by concurrent infusion of 1 and 10 microg/side D-cycloserine. These results suggest that positive modulation of the NMDA receptor/channel through activation of the glycine site can compensate dysfunction of hippocampal cholinergic neurotransmission involved in working memory function.
Parkinson's disease (PD) is an age-related neurodegenerative disorder that affects approximately 1 million persons in the United States. It is characterized by resting tremor, rigidity, bradykinesia or slowness, gait disturbance, and postural instability. Pathological features include degeneration of dopaminergic neurons in the substantia nigra pars compacta coupled with intracytoplasmic inclusions known as Lewy bodies. Neurodegeneration and Lewy bodies can also be found in the locus ceruleus, nucleus basalis, hypothalamus, cerebral cortex, cranial nerve motor nuclei, and central and peripheral components of the autonomic nervous system. Current treatment consists of a dopamine replacement strategy using primarily the dopamine precursor levodopa. While levodopa provides benefit to virtually all PD patients, after 5-10 years of treatment the majority of patients develop adverse events in the form of dyskinesia (involuntary movements) and fluctuations in motor response. Further, disease progression is associated with the development of dementia, autonomic dysfunction, and postural instability, which do not respond to levodopa therapy. Accordingly, research efforts have been directed toward understanding the etiology and pathogenesis of PD in the hope of developing a more effective therapy that will slow or halt the natural progression of PD. This paper reviews recent advances.
While screening extracts of natural products in search of anticholinesterase activity, we found that a total methanolic extract of the tuber of Corydalis ternata (Papaveraceae) showed significant inhibitory effects on acetylcholinesterase. Further fractionation of this extract using acetylcholinesterase inhibition as the parameter screened resulted in the isolation and purification of an alkaloid, protopine. Protopine inhibited acetylcholinesterase activity in a dose-dependent manner. The concentration required for 50% inhibition was 50 microM. The anti-acetylcholinesterase activity of protopine was specific reversible and competitive in manner. Furthermore, when mice were pretreated with protopine, the alkaloid significantly alleviated scopolamine-induced memory impairment. In fact, protopine had an efficacy almost identical to that of velnacrine, a tacrine derivative developed by a major drug manufacturer to treat Alzheimer's disease, at an identical therapeutic concentration. We suggest, therefore, that protopine has both anti-acetylcholinesterase and antiamnesic properties that may ultimately hold significant therapeutic value in alleviating certain memory impairments observed in dementia.
The effect of rivastigmine on memory impairments induced in rats by scopolamine (0.5 mg/kg) was assessed in the Morris water maze and passive avoidance tests and compared with that of tacrine (2.5-17.7 mg/kg). Rivastigmine, (0.5-2.5 mg/kg) inhibited cholinesterase in the cortex and hippocampus by 21-60% and antagonised the deficits in working and reference memory. Tacrine (12.5 and 17.7 mg/kg) produced significantly less inhibition of cholinesterase in the hippocampus but more in the striatum than rivastigmine (0.75 and 1.5 mg/kg) and only antagonised the deficit in reference memory. Rivastigmine (1.5 and 2.5 mg/kg) or tacrine (12.5 mg/kg), injected immediately after completion of the acquisition trial in the passive avoidance test, antagonised the deficit induced by scopolamine (1 mg/kg) in memory retention. The inability of higher doses of the cholinesterase inhibitors to antagonise memory deficits induced by scopolamine may be related to excessive cholinergic stimulation in the central nervous system.
The tripeptide glutathione is the thiol compound present in the highest concentration in cells of all organs. Glutathione has many physiological functions including its involvement in the defense against reactive oxygen species. The cells of the human brain consume about 20% of the oxygen utilized by the body but constitute only 2% of the body weight. Consequently, reactive oxygen species which are continuously generated during oxidative metabolism will be generated in high rates within the brain. Therefore, the detoxification of reactive oxygen species is an essential task within the brain and the involvement of the antioxidant glutathione in such processes is very important. The main focus of this review article will be recent results on glutathione metabolism of different brain cell types in culture. The glutathione content of brain cells depends strongly on the availability of precursors for glutathione. Different types of brain cells prefer different extracellular glutathione precursors. Glutathione is involved in the disposal of peroxides by brain cells and in the protection against reactive oxygen species. In coculture astroglial cells protect other neural cell types against the toxicity of various compounds. One mechanism for this interaction is the supply by astroglial cells of glutathione precursors to neighboring cells. Recent results confirm the prominent role of astrocytes in glutathione metabolism and the defense against reactive oxygen species in brain. These results also suggest an involvement of a compromised astroglial glutathione system in the oxidative stress reported for neurological disorders.
The fungus Inonotus obliquus (Pers.) Pil. synthesised high-molecular-weight phenolic pigments that were assigned to melanins according to their physicochemical properties. It was showed that copper ions (0.008%), pyrocatechol (1.0 mM), and tyrosine (20.0 mM) stimulated the melanogenesis. The production of melanin correlated with the synthesis of o- and p-diphenoloxidases. The fungal melanin had strong antioxidant and genoprotective effects.
Evidence of oxidative stress is apparent in both acute and chronic neurodegenerative diseases, such as stroke, Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Increased generation of reactive oxygen species simply overwhelm endogenous antioxidant defences, leading to subsequent oxidative damage and cell death. Tissue culture and animal models have been developed to mimic some of the biochemical changes and neuropathology found in these diseases. In doing so, it has been experimentally demonstrated that oxidative stress plays a critical role in neuronal cell death. Antioxidant enzymes, such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) have demonstrated therapeutic efficacy in models of neurodegeneration. However, delivery and stability issues have reduced the enthusiasm to clinically develop these proteins. Most recently, SOD mimetics, small molecules which mimic the activity of endogenous superoxide dismutase, have come to the forefront of antioxidant therapeutics. This review will examine the experimental evidence supporting the use of scavengers of superoxide anions in treating some neurodegenerative diseases, such as stroke, PD and ALS, but also the pitfalls that have met antioxidant molecules in clinical trials.
We previously reported that phenylpropanoids isolated from the roots of Scrophularia buergeriana Miquel (Scrophulariaceae) protected cultured cortical neurons against glutamate-induced neurotoxicity [Kim and Kim, Phytochemistry, 54 (2000) 503-509; Kim et al., Br. J. Pharmacol. 135 (2002) 1281-1291]. In the present study, we examined the anti-amnestic activities of phenylpropanoids in mice with amnesia induced in vivo by scopolamine. Among the phenylpropanoids tested through passive avoidance tasks, buergeriside A1, buergeriside C1, E-p-methoxycinnamic acid (E-p-MCA) and E-isoferulic acid significantly improved the deficit of memory induced by scopolamine. This suggested that the alpha,beta-unsaturated carboxyl moiety and the para-methoxy group in phenylpropanoids (E-p-MCA) might be a crucial component in their cognition-enhancing activity. Indeed, E-p-MCA (0.01-2 mg/kg body weight, i.p.), given in pre- or post-treatment paradigms, significantly ameliorated scopolamine-induced amnesia as determined by passive avoidance tasks and prevented or aided in the recovery of memory to a level that was about 60% of control. In addition, E-p-MCA (0.1-1.0 mg/kg body weight, i.p.) significantly improved impairments of spatial learning and memory induced by scopolamine; the compound reduced deficits in both long- and short-term memories as measured by the Morris water maze test. We suggest, therefore, that E-p-MCA may ultimately hold significant therapeutic value in alleviating certain memory impairments observed in dementia.
This study was designed to investigate if the impairment of learning and memory induced by acute administration of scopolamine (1.4 mg/kg ip) in rats is associated with altered brain oxidative stress status. The passive avoidance paradigm was used to assess retrieval memory of rats after scopolamine treatment. Following retrieval testing, biochemical assessments of malondialdehyde (MDA), glutathione peroxidase (GSHPx), glutathione (GSH), and superoxide dismutase (SOD) levels/activities as oxidative stress indices were performed. This study also investigated the effect of acute administration of Hypericum perforatum extract (4.0, 8.0, 12.0, and 25.0 mg/kg ip), containing flavonoids with documented antioxidant activity, on brain oxidative status of nai;ve rats treated with amnestic dose of scopolamine. Results showed that administration of 1.4 mg/kg of scopolamine impaired retrieval memory of rats and that such amnesia was associated with elevated MDA and reduced GSH brain levels. In nai;ve rats, which have not been exposed to conditioned fear, scopolamine administration also increased MDA and reduced GSH levels, although with an increase in brain GSHPx activity. Pretreatment of the animals with Hypericum extract (4, 8, and 12 mg/kg) resulted in an antioxidant effect through altering brain MDA, GSHPx, and/or GSH level/activity. Since oxidative stress is implicated in the pathophysiology of dementia, the findings of this study may substantiate the value of scopolamine-induced amnesia in rats as a valid animal model to screen for drugs with potential therapeutic benefit in dementia. Exposure of animals to conditioned fear may be suggested to impair the balance between the rate of lipid peroxidation and the activation of GSHPx as a compensatory antioxidant protective mechanism. It is also concluded that low doses of Hypericum extract, demonstrating antioxidant activity, may be of value for demented patients exhibiting elevated brain oxidative status. Since depression commonly coexists with dementia, Hypericum extract as a drug with documented antidepressant action may also be a better alternative than several other antidepressant medications that have not been evaluated to test their effect on brain oxidative status during amnesia.
Acetylcholinesterase (AChE, EC 3.1.1.7) inhibitors are the only registered drugs used to treat Alzheimer's disease (AD). New AChE inhibitors may contribute to the design of new pharmaceuticals and supply information which will facilitate the understanding of the interaction between inhibitors and the enzyme. The dried root of Salvia miltiorhiza is called 'Danshen' in China, and has been used for the treatment of cerebrovascular disease and CNS deterioration in old age for over one thousand years. In this work, a modified Ellman method was used to guide the fractionation of the active AChE inhibitory compounds from an acetone extract. Four inhibitory compounds, dihydrotanshinone, cryptotanshinone, tanshinone I and tanshinone IIA were isolated, and the structures were identified by comparison of their spectral characteristics with previous reports. The inhibitory activities of dihydrotanshinone and cryptotanshinone were dose-dependent, their IC (50) values being 1.0 microM and 7.0 microM, respectively. These two compounds were the major inhibitory compounds in the extract as judged by HPLC analysis, forming 0.054 % w/w and 0.23 % w/w in the dried root, respectively, and in mixture they appear to be less active than as isolated compounds. The clogP values of dihydrotanshinone, cryptotanshinone, tanshinone I and tanshinone IIA were calculated as 2.4, 3.4, 4.8 and 5.8, respectively, which indicate that these compounds have potential to penetrate the blood-brain barrier. This is the first example of diterpenoids as inhibitors of AChE.
In the present study, activity of salt soluble (SS) G1 and detergent soluble (DS) G4 molecular isoforms of acetylcholinesterase (AChE) has been investigated in rat brain areas in trained (learned), scopolamine (amnesic) and Tacrine (anti-dementic) treated rats to find out their role in learning and memory functions. AChE was estimated spectrophotometrically at 412 nm in rat brain areas. Isolation and partial purification of molecular isoforms G1 and G4 of AChE was done by gel filtration chromatography. Passive avoidance was used to test learning and memory functions. AChE activity was altered in both the fractions SS and DS of different brain areas following passive avoidance in control, scopolamine treated, tacrine treated and tacrine treatment in scopolamine pretreated rats. The peak AChE activity obtained in the DS (fraction 9) and the SS (fraction 13) fraction following gel filtration chromatography. On the basis of molecular weight fraction 9 (DS) and 13 (SS) represent the G4 and G1, respectively. The pattern of changes in the AChE activity of G1 isoform (fraction 13 of SS) and G4 isoform (fraction 9 of DS) in brain areas were similar to those of SS and DS fraction, respectively. In hippocampus, AChE activity in the fraction G1 isoform (fraction 13 of SS) was decreased only in tacrine treated rats but AChE activity in the G4 isoform (fraction 9 of DS) was decreased in both trained and tacrine treated rats. Changes in activity of G4 isoform of AChE in hippocampus could be correlated with passive avoidance learning, scopolamine induced deficit in passive avoidance and reversal of scopolamine deficit by tacrine.
Reactive oxygen species (ROS) and reactive nitrogen species (RNS, e.g. nitric oxide, NO(*)) are well recognised for playing a dual role as both deleterious and beneficial species. ROS and RNS are normally generated by tightly regulated enzymes, such as NO synthase (NOS) and NAD(P)H oxidase isoforms, respectively. Overproduction of ROS (arising either from mitochondrial electron-transport chain or excessive stimulation of NAD(P)H) results in oxidative stress, a deleterious process that can be an important mediator of damage to cell structures, including lipids and membranes, proteins, and DNA. In contrast, beneficial effects of ROS/RNS (e.g. superoxide radical and nitric oxide) occur at low/moderate concentrations and involve physiological roles in cellular responses to noxia, as for example in defence against infectious agents, in the function of a number of cellular signalling pathways, and the induction of a mitogenic response. Ironically, various ROS-mediated actions in fact protect cells against ROS-induced oxidative stress and re-establish or maintain "redox balance" termed also "redox homeostasis". The "two-faced" character of ROS is clearly substantiated. For example, a growing body of evidence shows that ROS within cells act as secondary messengers in intracellular signalling cascades which induce and maintain the oncogenic phenotype of cancer cells, however, ROS can also induce cellular senescence and apoptosis and can therefore function as anti-tumourigenic species. This review will describe the: (i) chemistry and biochemistry of ROS/RNS and sources of free radical generation; (ii) damage to DNA, to proteins, and to lipids by free radicals; (iii) role of antioxidants (e.g. glutathione) in the maintenance of cellular "redox homeostasis"; (iv) overview of ROS-induced signaling pathways; (v) role of ROS in redox regulation of normal physiological functions, as well as (vi) role of ROS in pathophysiological implications of altered redox regulation (human diseases and ageing). Attention is focussed on the ROS/RNS-linked pathogenesis of cancer, cardiovascular disease, atherosclerosis, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases (Alzheimer's disease and Parkinson's disease), rheumatoid arthritis, and ageing. Topics of current debate are also reviewed such as the question whether excessive formation of free radicals is a primary cause or a downstream consequence of tissue injury.
The fruiting body of Inonotus obliquus, a medicinal mushroom called chaga, has been used as a traditional medicine for cancer treatment. Although this mushroom has been known to exhibit potent antioxidant activity, the mechanisms responsible for this activity remain unknown. In our investigation for free radical scavengers from the methanolic extract of this mushroom, inonoblins A (1), B (2), and C (3) were isolated along with the known compounds, phelligridins D (4), E (5), and G (6). Their structures were established by extensive spectroscopic analyses. These compounds exhibited significant scavenging activity against the ABTS radical cation and DPPH radical, and showed moderate activity against the superoxide radical anion.
Age related changes in the glutathione S transferease and glutathione peroxidase activity of rat liver cytosol Spectrometric assay for superoxide dismutase based on the reduction of highly water soluble tetrazolium salts by xanthine oxidase
- V Z Lankin
- A K Tikhase
- A L Kovalevskaya
- V V Lemeshko
- A M Vikhert
30 V. Z. Lankin, A. K. Tikhase, A. L. Kovalevskaya, V. V. Lemeshko and A. M. Vikhert, Age related changes in the glutathione S transferease and glutathione peroxidase activity of rat liver cytosol, Dokl. Akad. Nauk SSSR, 1981, 261, 1467–1470. 31 U. Hiroyuki, K. Daisuke, M. Susumu and S. Masayoshi, Spectrometric assay for superoxide dismutase based on the reduction of highly water soluble tetrazolium salts by xanthine oxidase, Biosci., Biotechnol., Biochem., 1999, 63, 485–488.
- Hestrin